U.S. patent application number 15/938499 was filed with the patent office on 2018-07-26 for ear canal plug for detecting bio-electrical signals.
This patent application is currently assigned to T&W Engineering A/S. The applicant listed for this patent is T&W Engineering A/S. Invention is credited to Mikael ANDERSEN.
Application Number | 20180206788 15/938499 |
Document ID | / |
Family ID | 54252289 |
Filed Date | 2018-07-26 |
United States Patent
Application |
20180206788 |
Kind Code |
A1 |
ANDERSEN; Mikael |
July 26, 2018 |
EAR CANAL PLUG FOR DETECTING BIO-ELECTRICAL SIGNALS
Abstract
An ear plug (1) for arrangement in an ear canal includes at
least two electrodes (3) for detecting an EEG signal from a skin
surface when the ear plug is arranged in the ear canal. The ear
plug further includes a housing having an outer wall (2) made from
a resilient material, and a signal acquisition circuit (23). The
electrodes (3) are provided with a skin contact part (4) arranged
on an outside surface of the housing and connected through the
outer wall (2) of the housing to a supporting member (5) on the
inner part of the housing. The skin contact part (4) and the
supporting member (5) are arranged for clamping the outer wall
(2).
Inventors: |
ANDERSEN; Mikael; (Allerod,
DK) |
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Applicant: |
Name |
City |
State |
Country |
Type |
T&W Engineering A/S |
Lynge |
|
DK |
|
|
Assignee: |
T&W Engineering A/S
Lynge
DK
|
Family ID: |
54252289 |
Appl. No.: |
15/938499 |
Filed: |
March 28, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2015/072691 |
Oct 1, 2015 |
|
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15938499 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04R 25/652 20130101;
A61B 5/6817 20130101; A61B 2562/125 20130101; H04R 25/658 20130101;
A61B 5/0478 20130101; H04R 25/65 20130101; A61B 5/6867 20130101;
A61B 5/6847 20130101 |
International
Class: |
A61B 5/00 20060101
A61B005/00; A61B 5/0478 20060101 A61B005/0478 |
Claims
1. An ear plug for arrangement in an ear canal, the ear plug
comprising at least two electrodes prepared for detecting an EEG
signal from a skin surface when the ear plug is arranged in the ear
canal, a housing having an outer wall made from a resilient
material, and a signal acquisition circuit, the electrodes being
provided with a skin contact part arranged on an outside surface of
the housing and connected through the outer wall of the housing to
a supporting member on the inner part of the housing, the skin
contact part and the supporting member being arranged for clamping
the outer wall.
2. The ear plug according to claim 1, wherein the housing is
compressible and the electrodes are arranged to follow a movement
caused by a compression of the outer wall.
3. The ear plug according to claim 1, wherein the outer wall is
provided with a shape customized to the ear canal of an intended
user.
4. The ear plug according to claim 1, wherein the skin contact part
of the electrodes is provided with a layer of iridium oxide on at
least the surface intended to touch the skin surface.
5. The ear plug according to claim 4, wherein the layer of iridium
oxide also comprises tantalum.
6. The ear plug according to claim 4, wherein the layer of iridium
oxide is porous.
7. The ear plug according to claim 1, wherein each one of the at
least two electrodes is provided with an amplifying circuit, the
amplifying circuit being shielded against electromagnetic
interference.
8. The ear plug according to claim 1, wherein the amplifying
circuit is connected to a flex print circuit combining the signals
from the at least two electrodes.
9. The ear plug according to claim 1, wherein the skin contact part
is detachably connected to the supporting member through a
connecting part.
10. The ear plug according to claim 1, wherein the signal
acquisition circuit comprises an A/D converter.
11. The ear plug according to claim 1, wherein the outer wall is
adapted to exert a pressure against the ear canal wall when
inserted, in order to enhance electrical contact between the skin
contact parts of the at least two electrodes and the ear canal
wall.
12. An EEG monitor comprising an ear plug according to claim 1.
13. A hearing aid comprising an ear plug according to claim 1.
14. A method for manufacturing an EEG monitor comprising the steps
of: providing an ear plug housing having a resilient outer wall,
providing EEG electrodes, each electrode being separated into a
skin contact part and a supporting member, connecting the
supporting members to an electronic circuit, arranging the
supporting member with the electronic circuit inside the ear plug
housing, connecting the skin contact parts from the outside of the
ear plug housing to the supporting member through pre-arranged
holes in the outer wall, such that the skin contact part and the
supporting member is arranged for clamping the outer wall.
Description
[0001] This application is a continuation of Application No.
PCT/EP2015/072691 filed Oct. 1, 2015, the disclosure of which is
incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to an ear plug for detecting
bio-electrical signals. The invention relates more particularly to
an ear plug for arrangement in an ear canal, where the ear plug
comprises at least two electrodes prepared for detecting an EEG
signal from a skin surface when the ear plug is arranged in the ear
canal. The ear plug also comprises a housing with an outer wall
made from a resilient material, and further comprises a signal
acquisition circuit. The invention also relates to a method for
manufacturing the ear plug.
[0003] Bio-electrical signals are here understood to be electrical
potential differences across a tissue, organ or cell system or
originating from the human body. The best known examples are
Electrocardiogram (ECG) signals and Electroencephalogram (EEG)
signals. An ear plug for detecting bio-electrical signals in the
ear canal is made for arrangement fully or partly in the ear canal
of a person. The ear plug is mainly designed for the detection of
EEG signals.
[0004] EEG signals are electrical signals generated by a person's
brain activity. In recent years, EEG monitoring systems, that may
be carried or worn continuously by a person to be monitored, have
been devised. A goal is to have personal wearable EEG monitors
which can be carried without causing more inconvenience than
glasses or a modern small hearing aid, even when carried over an
extended interval of time, e.g. several months or years.
[0005] Such EEG monitors may be applied for purposes of
surveillance of a condition of the person and for providing some
kind of alarm or information in case predetermined conditions are
met. The monitor may also be applied for collection of data for
further analysis, e.g. for diagnostic purposes or for research use.
An example of an application is for surveillance of persons having
diabetes.
[0006] Measuring the EEG signal in the ear canal is known from WO
2011/000383 A1 disclosing an ear plug with EEG electrodes where the
ear plug shape is individually matched to the users ear canal.
[0007] In WO 2013/026481 A1 it is described that the electrodes can
be capacitive, i.e. being provided with a dielectric material on
the surface intended to contact the skin surface.
[0008] WO 2007/047667 A2 discloses an ear plug made from a
compressible material and provided with EEG electrodes.
[0009] One problem with the known solutions is that it is difficult
to obtain an ear plug with EEG electrodes which is both pleasant
and not annoying to wear for extended periods of time, and at the
same time can obtain a stable and reliable EEG signal.
SUMMARY OF THE INVENTION
[0010] A solution to this problem has been found by an ear plug
further having electrodes provided with a skin contact part
arranged on an outside surface of the ear plug housing and
connected through the outer wall of the housing to a supporting
member on the inner part of the housing. The skin contact part and
the supporting member are arranged for clamping the outer wall.
[0011] One advantage of the solution is that a flexible ear plug
which will adapt the shape of the ear canal is achieved. When the
outer wall of the ear plug housing is said to be made from a
resilient material, this is understood to include elastic as well
as viscoelastic materials
[0012] In an embodiment of the ear plug the housing is compressible
and the electrodes are arranged to follow a movement caused by a
compression of the outer wall. This has the advantage that the
whole ear plug is compressible as such, and not just the resilient
outer wall. Thereby, the risk that the ear plug becomes irritating
or annoying to wear over an extended period of time, such as
several month or years, becomes significantly reduced.
[0013] In a further embodiment of the ear plug the outer wall of
the housing is provided with a shape customized to the ear canal of
an intended user. This will also make the ear plug more pleasant to
wear and reduce the risk of annoyance or irritation.
[0014] In a further embodiment of the ear plug the skin contact
part of the electrodes is provided with a layer of iridium oxide on
at least the surface intended to touch the skin surface in ear,
e.g. the ear canal or concha part of the ear. This has the
advantage that a low impedance between skin and electrode can be
achieved, and that the risk of skin irritation is reduced. One
advantage of iridium oxide is that a relatively small geometric
area of an electrode can be applied, and still achieving a large
electrochemically effective area. When the layer of iridium oxide
also comprises tantalum, these advantages are more profound.
Concerning the low impedance, this is also the case when the layer
of iridium oxide is porous.
[0015] In a further embodiment of the ear plug each one of the at
least two electrodes are provided with an amplifying circuit, the
amplifying circuit being shielded against electromagnetic noise.
Thereby the electrodes are made into so called active electrodes,
where the signal delivered from the electrode is more powerful and
therefore less sensitive to noise. The amplifying circuit may also
have an analogue to digital (A/D) converter, making the signal from
the electrode even less sensitive to noise.
[0016] In a further embodiment of the ear plug the amplifying
circuit of the electrodes is connected to a flex print circuit
combining the signals from the at least two electrodes. This
provides for a mechanically flexible electronic platform, which can
follow compressions of the ear plug including the electrodes. This
flexible electronic platform can also be applied for mounting in
individually fitted ear plugs. Flexibility of the electronic
platform can also be achieved by use of wires, but this will be
more time consuming in the production process.
[0017] In a further embodiment of the ear plug the skin contact
part of the electrodes is detachabliy connected to the supporting
member of the electrodes through a connecting part. This allows for
assembling of the electrodes through holes in the outer wall of the
ear plug housing.
[0018] In a further embodiment of the ear plug, the outer wall is
adapted to exert a pressure against the ear canal wall when
inserted, in order to facilitate good electrical contact between
the skin contact parts of the electrodes and the ear canal
wall.
[0019] In general the use of a conductive gel may be applied for
improving the electrical connection between an EEG electrode and
the skin of the ear canal.
[0020] In an embodiment an ear plug as described above is applied
for an EEG monitor. The ear plug may comprise the whole EEG
monitor, or the ear plug may comprise some electrodes, while signal
processing, power supply, speaker for notifications etc. could be
arranged in a separate housing, e.g. to be arranged behind the
ear.
[0021] In another embodiment an ear plug described above is applied
for a hearing aid in which an EEG signal is detected and utilized
by the hearing aid. The utilization may be for better adjustment of
the hearing aid or for automatic program selection. This can be an
in the ear hearing aid, or for another hearing aid comprising an
ear plug part.
[0022] In a second aspect the invention is directed at a method for
manufacturing an ear plug. This method comprises the steps: 1)
providing an ear plug housing with a resilient outer wall; 2)
providing EEG electrodes, where each electrode is separated into a
skin contact part and a supporting member; 3) connecting the
supporting members to an electronic circuit; 4) arranging the
supporting member with the electronic circuit inside the ear plug
housing; 5) connecting the skin contact parts from the outside of
the ear plug housing to the supporting member through pre-arranged
holes (e.g. pre-stamped holes) in the outer wall, such that the
skin contact part and the supporting member are arranged for
clamping the outer wall. This manufacturing method has found to be
reliable and fast, especially in respect of providing ear plugs
with individually positioned electrodes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Embodiments of the invention will now be explained in
further detail with reference to the figures.
[0024] FIG. 1 illustrates an ear plug having EEG electrodes
arranged in a housing made from a resilient material.
[0025] FIG. 2 illustrates an EEG electrode with a washer for
holding the electrode.
[0026] FIG. 3 illustrates an inner housing for an ear plug, where
the inner housing has two extending EEG electrodes.
[0027] FIG. 4 illustrates an example of an EEG electrode without
separate washer.
[0028] FIG. 5 illustrates a further example of an EEG electrode
with a washer for holding the electrode.
[0029] FIG. 6 illustrates an example of an EEG electrode comprising
a module with an electronic circuit and connected with a signal
cable.
[0030] FIG. 7 illustrates the EEG electrode of FIG. 6 from a
different viewing angle.
[0031] FIG. 8 illustrates a flex print connected to three different
EEG electrodes.
[0032] FIG. 9 illustrates an exploded view of an EEG electrode.
[0033] FIG. 10 illustrates the exploded view of an electrode from
FIG. 9 but seen from a different angle.
[0034] FIG. 11 illustrates an EEG monitor based on an ear plug with
EEG electrodes arranged in a resilient wall.
[0035] FIG. 12 illustrates a hearing aid comprising an ear plug
with EEG electrodes.
DETAILED DESCRIPTION OF THE INVENTION
[0036] FIG. 1 shows an ear plug 1 which is supposed to be
individually fitted to an ear canal of a person. A first part 20 of
the ear plug 1 will be arranged in the ear canal and a second part
21 of the ear plug shown in FIG. 1 will be arranged in the concha
region or outside the ear canal. In other embodiments the whole ear
plug may be fitted into the ear canal. The ear plug 1 is shaped by
a wall 2 made of a resilient material, e.g. silicone. Two EEG
electrodes 3 are shown in the ear plug, but there could be three or
four. Each EEG electrode comprises a skin contact part 4, which
should obtain a good electrical contact with the skin of the person
when the ear plug 1 is in use. The skin contact part 4 is arranged
on the external side of the housing wall 2. The skin contact part 4
is connected by a connector 6, e.g. a metal pin, through the wall 2
to a supporting member 5 arranged on the inner side of the wall 2.
The supporting member 5 may be in the form of a washer. The two
electrodes shown are each connected with a wire 8 for transferring
the detected EEG signal, or an amplified EEG signal, to an
electronic module (not shown) for signal processing. This could be
in a signal acquisition circuit, which typically holds an
amplifier.
[0037] The ear plug shown in FIG. 1 could comprise more than the
two EEG electrodes shown. There could be e.g. a total of at least
three or at least four electrodes in the first part 20 of the ear
plug placed in the ear canal. Also, or alternatively, there could
be an electrode in the second part 21 of the ear plug arranged e.g.
in the concha. This concha electrode could function as a reference
electrode. The ear plug in FIG. 1 is further provided with an
opening 7 for an acoustic sound passage, in order to allow for
normal hearing for the person wearing the ear plug.
[0038] The housing wall 2, made from a resilient and soft material,
may be the structure providing the ear plug with its overall shape.
The wall 2 should be designed such that it will press the skin
contact part 4 of the electrodes against the skin in the ear canal.
This pressure should be high enough to provide a stable electrical
contact in order to detect an EEG signal. However, the pressure
should not be such that the person carrying the ear plug becomes
annoyed over long term use of the ear plug.
[0039] The thickness of the wall 2 could be constant for the entire
ear plug. The thickness of the wall 2 may, however, also be varied
in order to provide for a pressure being exerted by the EEG
electrodes 3 against the skin, but no pressure being exerted by any
other part of the ear plug. The wall should be thick enough to
ensure that it stays in the correct shape without any risk of
collapsing. Often the thickness will be in the range 0.5-3.0
mm.
[0040] The resilient material for the wall 2 may be an elastic
material or a viscoelastic material. A possible material for the
wall 2 is silicone, e.g. with a Shore hardness in the range 20-60,
but other materials could also be applied.
[0041] It is also possible that the inside space of the ear plug
could be filled with the resilient wall material, e.g. silicone,
except for space for electronics, connecting wires or flex print
and for an acoustic sound passage.
[0042] FIGS. 2 shows an example of an EEG electrode 3 comprising a
skin contact part 4, a pin connecting part 6 and a supporting
member 5. As also indicated in FIG. 1, the skin contact part and
the supporting member 5 will be arranged for clamping the wall
material of the ear plug housing, when assembled to the ear
plug.
[0043] In the embodiment of an EEG electrode shown in FIG. 2 the
skin contact part 4 are typically integrated with the connecting
part 6, e.g. manufactured from the same piece of metal. The
supporting member 5, e.g. a washer, is detachably connected to the
connecting part 6. This construction of the EEG electrode
facilitates an assembling method of the ear plug where the
supporting members to all electrodes to be arranged in the ear plug
are each first attached to a signal wire 8 which is connected to an
electronic circuit, or, the supporting members are each directly
connected to an electronic or a signal acquisition circuit, e.g.
including a pre-amplifier, from which there is a connection to one
electronic circuit. Then these supporting members 5, now connected
through wires, are arranged inside an ear plug housing. Each
supporting member is arranged on the inside of the ear plug housing
wall at a location where the intention is to place an EEG
electrode. A hole is made, e.g. stamped, in the wall, and the
connecting part 6 is pressed through and engages, e.g. by a snap
connection, with the supporting member 5.
[0044] In practice the wiring between the supporting members 5 and
the electronic may be made by flexible printed circuit boards, in
the following called flex print (see FIG. 8 and below). The
supporting member 5, e.g. a washer, is then soldered to the flex
print.
[0045] If the connecting part 6 has a cylindrical shape, as
indicated in FIG. 2, a circumferential groove could be provided in
order for the supporting member to click in correct position in
this groove.
[0046] The embodiment in FIG. 2 is shown with the skin contact part
4 and the pin connecting part 6 centered on the same center axis.
This is one possibility, but also different options are possible.
E.g. the pin connecting part 6 could be arranged towards the outer
circular edge of the skin contact part 4. Such a design will
facilitate the manufacturing of a combined skin contact part 4 and
pin connecting part 6 from one sheet material, where the combined
skin contact part 4 and pin connecting part 6 are punched from the
sheet material, after which the pin connecting part 6 is bent in an
angle of 90 degrees or substantially 90 degrees in relation to the
surface area of the skin contact part 4.
[0047] The skin contact part 4 is preferably made from a material
giving a good electrical contact to the skin, being durable in the
humid environment, and being nontoxic and not irritant to the skin.
An example of a possible material could be titanium with a surface
coating of iridium oxide. Further examples of materials are found
in EP 1 237 621 B1, paragraph [0016]. Iridium oxide provides an
electrode with relatively low skin contact impedance when used as
dry electrode.
[0048] The pin connecting part 6 will often have a diameter of 1 mm
if having a circular cross sectional shape. The diameter of the
skin contact part can be in the range 3-4 mm, or in the range less
than 3.5 mm. The thickness of the skin contact part will often be
in the range of 0.25-0.5 mm.
[0049] FIG. 3 shows an embodiment where an inner shell 10 is
provided for the housing. The inner shell 10 is preferably made
from a non resilient material, e.g. acrylic. The electrodes 3 can
be arranged on this shell 10 with electrical connection to an
electronic circuit, and with connection to wiring or a flex print
arranged inside the shell 10.
[0050] After the inner shell 10 has been prepared with electrodes,
electronic circuit and electrical connections in form of wires
and/or flex print inside, the resilient outer wall 2 is arranged on
the outside of the shell 10. The resilient outer wall 2 is pulled
over the inner shell 10 with the electrodes 3, and subsequently the
skin contact part 4 of the electrodes 3 are pressed through pre
stamped holes in the resilient outer wall material. The outer wall
material will need to be sufficiently elastic for this purpose.
Alternatively, the resilient outer wall 2 may be casted directly on
the inner shell.
[0051] Often the ear plug will be provided with a through going
hole having a sufficient diameter not to obstruct the sound passage
to the eardrum at a level where discernable occlusion of the sound
is introduced. The position of this opening or hole is indicated by
reference 12, and the opening continues through the extension 11 of
the inner shell. The diameter of this opening or hole is at least
1.5 mm, preferably at least 2 mm, and more preferably at least 2.5
mm.
[0052] In general, all embodiments may be provided with a through
going opening or hole in order not to obstruct the sound passage.
The diameter may be as mentioned above, or, if the opening does not
have a circular cross sectional shape, the cross sectional area may
be at least 1.8 mm.sup.2, preferably at least 3.2 mm.sup.2, and
more preferably at least 5.0 mm.sup.2. mm.
[0053] FIG. 4 shows an embodiment of the electrode 3 where the
supporting member 5 is fixedly attached to the connector 6 and the
supporting part is provided with a shape facilitating easily
pressing the supporting member with the conical part 16 first
through a stamped hole in the outer housing wall 2. The resilient
housing wall 2 should be clamped between the supporting member 5
and the inner side 14 of the skin contact part 4 when positioned
correctly. The material forming the hole in the resilient housing
wall 2 should preferably also abut against the connector part 6 in
order to limit the transport of dirt and humidity through any leaks
around the connector part 6.
[0054] When the conical part 16 and the supporting member 5 have
been pressed through the resilient housing wall it should be
connected to the circuit inside the housing. A circumferential
groove 15 may be applied for this connection.
[0055] FIG. 5 shows an electrode where the supporting member 5 is a
washer for holding the electrode. As for the embodiment of FIG. 3
the washer 5 in FIG. 5 is first fixed to the electronics e.g. by a
wire, or soldered directly to a flex print. Then the connector 6,
which is attached to the skin contact part 4 is pushed through the
resilient outer wall 2, e.g. through a pre stamped hole. The
connector 6 and the washer 5 may be adapted for locking in a
position where the washer 5 and the skin contact part 4 are
clamping the resilient outer wall. The fixation of the connector 6
in the washer 5 may also be obtained by soldering or gluing.
However, a good electrical contact between the two parts should be
obtained.
[0056] FIG. 6 shows an embodiment of the electrode for the ear
plug, where a signal acquisition circuit (not shown) comprising
e.g. a pre-amplifier or an A/D converter is arranged in the
supporting member 5 or in the connecting member 6. The connecting
member 6 comprises an inner connecting part 61 (see FIG. 9) and an
outer connecting part 62, where the inner connecting part 61 is
integral with the skin contact part 4, e.g. shaped from the same
piece of material. The outer connecting part 62 is integral with
the supporting member 5, and forms an electronic housing 25 (see
FIGS. 8 and 9) which is made from an electrically insulating
material, e.g. a ceramic, a polymer or different types of plastic,
coated on its outer surface with a conductive layer in order to
obtain electromagnetic shielding of electronic circuit and any
signal path. There is a band 13 around the outer connecting part
62, where there is no conductive layer, in order to insulate the
electrode or the skin contact part 4 from the shielding, so that
the EEG signal is not short circuited. In FIG. 6 wires 19 from the
connecting cable 8 are seen. Also a sealant 17, e.g. glue, for
protection of the wires, is shown. The shielding of the supporting
member 5 will also provide some protection of the skin contact part
4 against electromagnetic noise. The shielding may be active or
passive, where active shielding is that the shield is provided with
the same potential as the signal wire and consequently there is no
potential between the signal wire and the shield. WO 2013/026481 A1
describes this.
[0057] FIG. 7 shows the electrode of FIG. 6, but from a different
angle, thereby illustrating the wires 19 connecting to pads 18 on a
circuit board (e.g. a thick film circuit board). FIG. 8 illustrates
three electrodes 3 for an ear plug connected by flex print
connections 8. The electrodes are here illustrated (partly in
exploded views) as active electrodes, meaning that a signal
acquisition circuit, e.g. comprising an amplifier and/or an A/D
converter, is arranged at, or behind, the skin contact part, which
is also what FIGS. 6 and 7 show. The active electrodes need power
supply lines as well as signal lines through the flex print
connections 8. The flexibility of the flex print connections 8
means that the electrodes 3 can be placed individually in the ear
plug 1. This can be an advantage in connection with customized ear
plugs since different persons have different ear channels, and the
optimal positions for best detecting an EEG signal in the ear canal
may be different from person to person. Also, the difference in
geometry of the ear channels of different persons may necessitate
different positions of the electrodes.
[0058] The bending 27 in one of the three flex print connections in
FIG. 8 makes it possible to mount all electrodes and supporting
members on the same side of a flat flex print piece, and still let
one of the electrodes face in the opposite direction when mounting
the flex print in the ear plug.
[0059] The flex print connections of FIG. 8 may also be applied in
connection with passive electrodes, where amplifiers, A/D
converters etc. could be arranged at a central flex print part 9,
to which the different flex print connections 8 are connected. In
such an embodiment shielding of the signal wires on the flex print
connections 8 may be preferred.
[0060] The ear plug in the different embodiments described may be
made as a customized ear plug by fitting the size and shape exactly
to the size and shape of the ear canal of the person to use the ear
plug. The ear plug can also be made as a standard ear plug in
different preselected sizes, where each person will have to select
the size fitting best. The resiliency of the outer wall of the ear
plug will facilitate the use of standard sizes, since each standard
size ear plug can be slightly compressed and will therefor fit a
smaller range of ear canal sizes.
[0061] FIGS. 9 and 10 shows enlarged exploded views of the
electrodes from FIG. 8. The electrode comprises the skin contact
part 4 integrated with the inner connecting part 61. This may be
made from titanium with a surface coating of iridium oxide, e.g.
only on or primarily on the surface intended to be in contact with
the skin. The amplifying circuit 23 is arranged on a chip. This
chip may also comprise and A/D converter. The chip is placed on a
circuit board 24 which is arranged in the electronic housing 25.
The electronic housing 25 is provided with a shielding layer made
from an electrically conductive material as mentioned above. The
electronic housing 25 comprises the outer connecting part 62 as
well as the supporting member 5, which two parts are integrally
connected, e.g. made from the same piece of material.
[0062] A flex print connecting part 8 may also be connected to the
electronic housing 25 and to the circuit board 24 (which could be a
thick film module) comprising a chip 23 and possibly also other
components. A cover 26 is arranged for covering the circuit board
24 and chip 23, and is made from, or coated with a conductive
material in order to ensure a complete shielding of the electronic.
The cover 26 is preferably also connected to neutral or ground on
the flex print connector 8.
[0063] In the manufacturing of an ear plug comprising electrodes
according to embodiments of FIGS. 6-10 there are at least two
possibilities. The first is that the skin contact part 4 of the
fully assembled electrode 3 is pushed through holes in the
resilient, and elastic, outer wall material. The second is that the
electrode before assembly is in two parts, one with the electronic
housing 25 with amplifying circuit 23 electronic circuit board 24,
and connections 8, and the other part being the skin contact part 4
with the inner connecting part 61. The ear plug is then assembled
by pushing the outer connecting part 62 into holes in the resilient
outer wall from the inside of the ear plug, and then pushing the
skin contact part 4 with the inner connecting part 61 into the
outer connecting part 62 from the outside of the ear plug.
[0064] One advantage of providing the ear plug of FIG. 1 with an
electrode according to FIG. 2, FIG. 4-7 or FIG. 9-10, is that when
these electrodes are only connected by a thin or flexible wire or
flex print, they will not affect the flexibility and
compressibility of the ear plug housing or the outer wall 2 of this
housing. I.e. the overall flexibility or resiliency which the
resilient wall 2 can provide to the ear plug, can be maintained
when supplying the ear plug with electrodes according to these
figures or similar types, and where these electrodes are connected
to electronic circuits by flexible wires or flex print. In this way
the electrodes will follow movements of the outer wall, both when
the ear plug is compressed and when the ear plug exerts a pressure
on the skin in the ear canal.
[0065] As mentioned a preferred thickness of the wall 2 is 0.5-3
mm. But the inner part of the ear plug can also be filled with the
same resilient material as the material used for the wall 2. This
filling may leave space for a ventilation and sound passage
channel. The ear plug with all resilient material may be casted in
one process around the electrodes, supporting members, electronic
circuit and connections.
[0066] FIG. 11 shows an example of an EEG monitor 30 built into an
ear plug 1 with a resilient outer wall 2, an electronic circuit 24
connected with two EEG electrodes 3 and an acoustic sound passage
31. The EEG monitor is adapted for placement in the ear canal, and
it is provided with a speaker 33 at a sound opening 34. The speaker
can be applied for providing alarms or notifications to the person
wearing the EEG monitor 30. The end of the EEG monitor provided
with the sound opening 34 is intended to face the inner part of the
ear canal, i.e. the eardrum, when in use.
[0067] FIG. 12 shows an example of a hearing aid 40 built into an
ear plug 1 with a resilient outer wall 2 and provided with EEG
electrodes 3. The hearing aid 40 is provided with a microphone 45
arranged at a microphone inlet 46. The microphone is connected to
an electronic circuit 24 provided with means for sound
amplification and processing (not shown). The circuit 24 delivers a
processed signal to a receiver 43 generating an acoustic sound
through the sound opening 44, which is facing the eardrum when the
hearing aid 40 is arranged in the ear canal. The hearing aid
further comprises a vent 41 for reducing the occlusion effect of
the hearing aid.
[0068] In a hearing aid, detection and analysis of the hearing aid
user's EEG signal may be applied for adjustment of the hearing aid.
This could be as described in WO 2011/006681 A1.
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